I have one other vertical pair of pink Washingtons, I have not soaked off, and left on 'cover', so the straight edge is not under question, and I do not do harm, by my inexperience of attempting to soak it off, before I have better practice.

I also did a photoshop of the stamps, to get a better look at the perfs, and make sure it wasn't a case of someone lining them up very well, that they are, indeed, connected.

I'm not assuming these are 248a's, but a vertical pair of 248, with a vertical straight edge, not a horizontal one.
Pink, Type I, since the lines through the triangle are not lighter on the inside,

would make this a 248, yes? A confirmation, or correction, and comments, are appreciated.